Condenser tester



Feb. 25, 1936. M. P. M CARTY CONDENSER TESTER Filed Feb. 3, 1933 EEEWJ [$20730]; JP/Vfllzrig INVENTO ATTORNEY Patented Feb. 25, 1936 o STATES PATENT OFFICE CONDENSER TESTER Madison P. McCarty, Dallas, Tex., assignor of one-half to Clarence E. Boren, Dallas, Tex.

Application February 3, 1933, Serial No. 655,075

1 Claim. (01. 175-183) Thi i venti relat s to lectri al testing deof a combination of electrical elements including vices and it has particular reference to a device a neon bulb or tube and so related and arranged or instrument for testing electrical condensers. in an electrical circuit a to P o the desired The principal object of the invention is to proeffect, i. e., to visibly reveal the defects in a convide an instrument of the character specified by denser y the behavior of the neon bulb. Accordwhich to test electrical condensers and particuy, reference is primari y ade to Figure 1 larly th types d i th i iti system of wherein is showna diagrammatic view of an elecautomobile vehicles but not necessarily restricttrifle-1 cui W ch may be eifectively used in ed to such use, since it may be also employed for Carrying Out the invention n p fie formtesting condensers forming a part of the electri- This Circuit is pa e to the c rcuit shown 10 cal equipment of radios and in any other cases i Figure 2 wherein it is modified. In Figure 2 where condensers are used, is a transformer I having a primary winding 2 Another object of the invention is to provide n onnect d t a sourc of lternatin c rr n a quick and simple means for testing condensers not shown, through Wires 3 p ovi ed wi h a which indicates visibly the fitness of the conswitch e n a y winding of the trans- 15 denser for its intended use and further to provide former I is shown at 5 and of suitable ratio for an instrument of simple and inexpensive conuses intended t n 5 iIO upp y S ab e urstruction and simple circuit or circuits, It fr rent for heating the filament I of a conventional quently happens that a condenser will show faulrectifying element The grid d plate of t s 2) ty under ordinary circumstances and c ntube 8 are connected together to form a two ele- 2n tional tests and might be declared worthless when, ment rectifier to thus produce half wave rectified as a matter of fact, it may not be defective and Current at the switch Points 9 an A Convice versa. denser l l, of suitable capacity is connected across Still another object of the invention is to enthe switch Points 9 and to smooth o t the 2:, able a condenser to be tested without the necespea o the half wave rectified current and o sity for special application or electrical knowla se the Voltageedge on the part of the operator, it being re- A double pole, double throw switch I2 is pro quired simply to attach suitable connections to Vided in t e rc Shown n ure 2 and has a the terminals of the condenser under test and jump r 13 a r n pai f the wi h points.

upon closing the circuit of the invention, the on bulb having O terminal connected to 30 fitness of the condenser for service will be reone blade of the switch l2, through wire l5 and vealed by the reaction in a neon or other gas the other terminal arranged to be connected to filled tube or bulb. one terminal of a condenser l6 under test through Another object of the invention is to provide wire I! and dotted connection [8. The other an instrument which is simple in operation and terminal of the condenser I6 is connected to the 35 positive in results so that the most inexperienced other blade of the switch l2 through the dotted mechanic or the layman can test any condenser connection I9 indicating one of the flexible leads, with positive accuracy by following the few simand wire 20. ple directions printed on the instrument. A high resistance 2| of one'megohm or more is 40 With the foregoing objects as paramount, the shunted across the neon bulb M to eliminate the 40 invention has particular reference to its salient slight glow of the neon bulb present or manifestfeatures of construction and arrangement of ed when certain types of paper insulated conparts which will become manifest as the descripdensers are tested. A momentary contact switch tion proceeds, taken in connection with the acor push button 22, normally open, is shunted companying drawing, wherein: across the neon bulb M for the purpose of throw- 45 Figure 1 is a diagrammatic view of one type ing the full potential in the circuit across the of circuit employed in the present invention. condenser l6 under test.

Figure 2 shows the circuit in Figure 1 modified. When the blades of the switch I 2 are in con- Figure 3 is another form of circuit which may tact with the switch points 9 and I0 and the be employed in the present invention, and switch 4 closed. supplying alternating current to 50 Figure 4 is a modified form of the circuit the transformer primary 2, the alternating curshown in Figure 3. rent induced in the transformer secondary 5 and Continuing with a more detailed description rectified by the tube 8, stabilized and voltage inof the drawing, it may he first mentioned that the creased by the condenser l l, passes through the invention comprehends primarily the provision neon bulb or tube ll to the condenser I6 55 ing 32.

under test. Thus the condenser 6 under test becomes charged to the full voltage being maintained in the circuit. The fitness of the condenser for normal service therefore is obviously indicated by the behavior of the neon bulb l4.

When a condenser is tested with the circuit shown in Figure 2 and as above described, the neon bulb M will flash once when contact with the condenser is first established providing the condenser is good, thus showing that the condenser will take a charge and is not open circuited and not shorted. A leaking condenser will cause the neon bulb to flash intermittently, the

"rapidity or frequency of flashes being determined by the extent of the leak. The greater the leak, the more rapid the recurrence of the flashes. A shorted condenser will cause the neon bulb to glow continuously or steadily on one of its electrodes and an open circuited condenser under test will cause the neon bulb to fail to glow. If the blades of the switch |2 are thrown into contact with the shorting jumper l3 when a condenser 6 is in a' charged condition the condenser will discharge through the neon bulb l4, causing a flash on one electrode opposite the electrode that showed the flash when the condenser was charged. The intensity or value of the flash gives a comparative indication of the capacity of the condenser. The dotted lines I 8 and I 9 in Figure 2 are suggestive of flexible leads or test prods, as previously mentioned.

Referring again to Figure 1, it will be noted that there is little difference between the circuit just described and that shown in this figure, the principal difference being in the omission of the double pole, double throw switch l2 and the high resistance 2| and push button switch 22. The circuit in Figure 1 also lacks the condenser I I. This circuit includes only the A. C. lines 23 and 24 with the transformer 25. The rectifier tube 26 is included in a circuit with the neon bulb 21 as in the preceding instances. The condenser under test is designated at 28 and to which connection is made through leads 29 and 30.

Referring to Figure 4, a further modified circuit is shown and which comprises a transformer 3|, having a primary winding 32 and connected to A. C. source through wires 33 and 34 and switch 35. The secondary winding is shown at 36 and is connected to the rectifier tube 31 through the wires 38 and 38a and is of sufficient ratio to supply current to heat the filament of this tube.

A jumper 39 connects one side of the supply circuit 34 and primary winding 32 with one side of the secondary winding 36 in such manner that the voltage induced in the secondary winding 36 will be additive in relation to the voltage impressed across the primary wind- The other side of the primary winding and supply circuit is connected by the wire 46 to the switch point 4| and the grid and plate of the tube 31 are connected to the switch point 42. Thus a half wave rectified current is delivered to the points 4| and 42. It will be notedthat the circuit in Figure 4 beyond the rectifier tube 31 is precisely the same as that part of the circuit shown in Figure 2, previously described. This portion of the circuit includes a condenser 43 and a switch 44 comparable to the switch l2 shown in Figure 2 as is likewise the neon tube 45, high resistance 46 and switch 41. The condenser under test is shown at 49.

The circuit shown in Figure 3 is similar to the circuit just described and illustrated in Figure 4 except that in this circuit, the condenser 43, switch 44, high resistance 46, and switch 41 are omitted. This circuit includes the A. C. wires 50 and 5| and the transformer 52 having connection through the jumper-52 t and tap 53 to the rectifying element 54. Wires 55 and 56 complete the circuit through the neon tube 57 and the condenser 58 under test.

The purpose of the transformer designated at 52in Figure 3 and at 3| in Figure 4 is to provide current to heat the filament of the rectifying element in each instance, also to add the voltage of the secondary of same to the output circuit.

The rectifying element serves to rectify the A. C. to half wave pulsating D. C. as previously set forth in the foregoing. The condensers H and 43 serve to smooth out the rectified D. C. and to increase the voltage and mini-amperage in the circuit.

In the drawing, the rectifying element is represented as a .three element vacuum tube converted into a twoelement rectifier by connecting together the grid and plate. Such tubes connected in this manner are inexpensive, however any kind of suitable rectifying tube or element may be efiectively used.

When a condenser is to be tested it is connected in multiple with the condenser in the testing instrument, the switch I2 is closed, whereupon the condenser under test becomes charged. The neon tube flashes as explained by reason of the current flow established therethrough and an electrical balance is obtained which remains constant, provided the condenser under test is not defective.

45 It will be readily understood from the foregoing by those skilled in the art, that any other electrical element or circuit inserted between the contact terminals for testing condensers, may

likewise be tested and the results observed from 50 the actions of the neon tube.

Manifestly, the construction shown is capable of considerable modification and such modification as is considered within the scope and meaning of theappended' claim is also considered 55 within the spirit and intent of the invention.

What is claimed is: e A condenser testing circuit comprising a neon tube, a rectifier, terminals for connecting a con denser in series with the rectifier and tube, and 30 means for .uniting said circuit to an alternating current supply circuit.

MADISON P. MOCARTY. 

